Stabilized fat-soluble vitamin and method of making same



, through into the ultimate granules.

centrated' at the center of the particle.

United StatesPate'nt O STABILIZED FAT-SOLUBLE VITAMIN AND METHOD OFMAKING SAME Adolf Rosenberg, Forest Hills, NY.

No Drawing. Application July 2, 1953 Serial No. 365,788

1 Claims. (Cl. 99- 2) This invention relates to feeds or supplementsoffeeds fortified with the fat-soluble vitamins. More particularly,

2,937,091 Patented 17,. 1eso to achieve the stabilization of the fatsoluble vitamins,

it 'is directed to a novel dry composition containing the fat-solublevitamins in a highly stabilized and physiologi pally available form. Theprovision of means for fortifying feeds Wlth supplements containing thefat-soluble vitamins in assuredjpotencies isa problem which hascommanded a vast amount of attention from scientists and technologists.Initially, it was thought suflicient to provide the fat-soluble vitaminsfor feed supplementation in such form that, until incorporation thereofin the feed, the vitamin content thereof was stabilized so asto'withstand destruction or disintegration; and, further, that the feedscontaining such supplements should exhibit a retentionofthevitaminpotency corporation in the feed. However, an even greater andmore perplexing problem exists'with respect to providing 2,496,634). Hissolution to the problem resided in providing dry, discrete particles ofa high melting fat ern-. bodying the fat-soluble vitamins, whichparticles or granules are distributed in a powdery base, as of soy flouror soy meal, as a protective vehicle. The particles are made byincorporating the fat-soluble vitamins in a molten fatty base, andsubsequently manipulating the mass-of molten fat with the vitaminsdistributed uniformly there- However, the Melnick' product cannot beincorporated as a component of a mineral concentrate used for thepurposes above described. In the presence of theminerals, the Melnickproduct suffers severe rapid destruction of the vitamins, especial-1yvitamin A. j

In'my co-pending application, Serial No. 220,333, filed April 10, 1951,I have described a product which consists of dry, discrete particles orgranules embodying the fatsoluble vitamins, as for example vitamin A.Those particles differ from the Melnick particles in that the bulk ofthe vitamin A therein is substantially disposed or con- In thoseparticles the vitamin portion constitutes a core which is encased by afatty shell or skin that'insulates the vitamin againstthe attack of thedestructive agents. In my copending application I have shown that suchencasement of the vitaminrich core by a fatty shell or skin can beachieved by using 'soya flour as a means for absorbing or seizing thevitamin and carrying it to the center of the sphere.

I have described therein a method of producing the especially vitamin A,by incorporating the vitamin in dry, discrete granules, as initiated byMelnick, it. was sought to utilize fats of high melting point. Othershave striven to use carriers or vehicles of even higher melting pointsso i as better to protect the vitamins against oxidation.

However,- the employment of carriers or vehicles having inordinatelyhigh melting points offers no true solution to. the problem, becauseinordinately high melting points interfere with the physiologicalavailability of the vitamin. If, for example, a labil'efvitamin beenclosed or encased in a tin or aluminum shell, the vitamin would bestabilized against the destructive effects of oxidation. If such anencapsulated vitamin is made a component ofa mineral concentrate, thetin or aluminum shell, indeed, provides a barrier .against the oxidativeaction, particularly the catalytic inducement of oxidation by minutequantities of iron and copper in the mineral mixture. But, it will beobvious that the physiological availability of the vitaminin'such'aproduct would be nil unless the digestive process of the animal were ofsuch sutficient chemical reactivity as to dissolve the metal shell andthereby release the vitamin. "In coping with this problem of providingdry, discrete granules which can be used for furnishing supplements offat-soluble vitamins that can be incorporated in mineral concentrates soas to provide complete supplements for the basic ration, I have soughtto discover means vfor achieving an encapsulation of the vitamins thatprovides an even more efiiective barrier against oxidative influencesthan does the fatty shell or skin of the granules described in myaforesaid co-pendin'g application. I e

It is recognized that encapsulation of labile vitamins in the form ofpharmaceutical tablets or capsules is old in the art. Such products are,however, unsuited for use as feed supplements since one animal orbird'in one feeding might obtain a super dose of thevitamin at theexpense of that allocated wall the animals or birds receiving thefeeding with the vitamin supplement. This makes it mandatory that thevitamin supplement be encapsulated for protective purposes inexceedingly small spheres or beads of diameters of not more than'2 mm.Whereas each sphere may be of high vitamin potency per unit weight, thevery large number required to fortify the feed makes for uniformfortification of the entire feed, it is this problem of protectiveencapsulation'of minute spheres containing the labile, fat-solublevitamin materialxwithl whichmy aforesaid co-pending application and thepresent application are concerned.

In the course of myinvestigation's" I' discovered that the encasement ofthe vitamin contained inthe fatty core by a shell that is anefiectiveLbarrier against-the oxidative activity above described couldbeachieved by meansof a proteinaceous shell which possesses-markedphysical stability but is,-nevertheless,soluble in the an mentary tract.Indeed, as will be shown hereinafter, that physical stability is coupledwith insolubility in water and even in the stomach-secretions. Theactual solution of-the shell takes place in the animals intestinaltract-so that the vitamin is released only in that part of thealimentarytract where, as scientific investigations are now bringing to light,thevitamin is in fact utilized.

In this connection it is to be noted that apparently anomalous resultsin bio assays of vitamin A (findings of potencies' exceeding thetheoretical or those found by chemical tests) of products made inaccordance with the encapsulating proceduresdescribed in my co-pendingapplication are due to the fact that when vitamin A is fed oradministered 'in the form of non-encapsulated fish liver oil, a portionthereof undergoes partial destruction in the upper part of thealimentary tract (the stomach) so that only a fraction of the ingestedvitamin is actually utilized in the physiological process.

As has been mentioned, the vitamin content of Melnicks product is unableto withstand the destructive ef- 'fects of minerals. Thus, I have foundthat when' one (1) part of the Melnick product (his example III) isincorporated in one (1) part of the following mineral concentrate:

answer- Grams Manganese sulfate, MnSO .4H- O 74- Potassium iodide, KI 6Ferrous sulfate, FeSO .4H O '73 Copper sulfate, CuSO .5H O 11 Zincsulfate, ZnSO .7I-I O 4 v Cobalt sulfate, CoSO .H O 0.6 Calciumcarbonate, q.s. 20 pounds.

to provide a product containing 280 U.S.P. units of vitamin A per gram,the retention of the vitamin A therein is very poor. The mixture shows aloss of from 95 percent to 100 percent of the vitamin A at the half-waystage of the storage period, i.e., 10 days at 45 C., the equivalent of 3months at room temperature.

The destruction of the vitamin D also under those conditions, althoughnot as complete as vitamin A, is, however, severe. Mineral mixturesfortified with the Melnick compositions to'an initial potency of 100U.S.P. units of vitamin D per gram show a destruction of that vitamin offrom 50 to 60 percent at the end of ten (10) .days storage at 45 C.

In my studies, vitamin A was determined according to the method of H. 0.Schaefier, J .A.O.A.C., volume 33, page 615 (1950), subject to the USP.XIII biological assay for confirmatory purposes, and vitamin D by thechick-bone-ash method, as described in A.O.A.C., sixth edition (1945).

It is to be noted that since mineral supplements are per seindestructible, they are, therefore, stored for much longer periods thanother'feed supplements prior to usel Suppliers of such supplements tofeed manufacturers or to farmers can not tolerate such excessive lossesof the costly vitamins. combine both minerals and-vitamins withguaranteed vitamin potencies do not exist.

In a compromise but very limited solution of the problem, the mineralmixture is diluted with quality protein supplements (fish meal, milkprotein, meat scrap, etc), viz; one part minerals two parts protein; andsuch mineral and protein mixture is supplemented with the stabilizedvitamin preparations of Melnick. A rapid turnover (short storage period)of theproduct is encouraged, but infrequently observed. But even herethevitamin A losses are still large, 60 to 83 percent of the vitamin Abeingdestroyed within the first 10 days at 45 C. or 3 months at ordinarytemperatures (initially 86 U.S;P. units per gram). Therefore; suchprotein mincral-vitamin supplements must not only 'be manufactured withhuge overages of the labile vitamins, but they also must be consumedwithin a period of less than 3 months after vitamin fortification-ifthey are to evidence nutritional value. It is clear that such initialsurcharging of a product with the labile vitamins, in order to providean adequate vitamin potency when it is fed to the animals is not onlyeconomically wasteful, but results in the pricing thereof at aninordinately high figure.

Since it is recognized that a deficiency in the ration of Hence,complete supplements which r base.

one essential nutrient, viz., the vitamin A, interferes with animalgrowth, reproduction and even survival, despite liberal quantities ofthe other nutrients, feed manufacturers furnishing the raisers of farmanimals with a ration supplements have longed for a solution to theirproblem of assuring that the vitamin A, E, or D potency of their productwill indeed be adequate at the time of feeding.

Thefailure of the vitamin A in Melnicks compositions to be as stable infeeds and in mineral supplements, as in the compositions themselves, isattributable in part to separation of the vitamin A in the fat granulesfrom the protective influenceo-fthe antioxidants in the soy flour Theaddition of one part of Melnicks composition, the vitamin containinggranules in the powdery base, to 99 parts of a feed, even one containingsoybean meal in concentrations of 30 percent reduces the protectiveinfiuence on the vitaminA of the antioxidants in the Melnick soy flourbase. Whereas the vitaminA product itself contains only soybean meal orflour around the fat particles embodying the vitamin A, in the feed, onthe contrary, there are at-least two parts of the other types of feedconstituents per one part of the soybean meal which are in contact withthe vitamin A component. Melnick has shown that other bases are inferiorto soybean meal -or soybean flour in protecting the vitamin A granules.This observation has been confirmed by publications from otherlaboratories (Wall, M. E., and Kelley, E. J., Ind. and Eng. Chem, vol.43, p'. 1146 .(1951);:Burns, M. 1., and Quackenbush, F. W., Ind. andEng. Chem., vol. 43,.p. 1952 (1951)).

In the case of mineral supplements fortified with Mel nickscompositions, there is still'another and more seri ous factor thatcontributes to the oxidative loss of the fat-soluble vitamins.- Themineral supplements contain, in plentifulquantity, the so-called traceminerals iron and copper, notorious for their influence in promoting therapid oxidation of both fats and vitamin A. Even if iron and coppersalts arenot deliberately included as components of some mineralsupplements, the other mineral salts furnish, as contaminants,substantial quantities ofthese essential elements. A good-poultry rationwill provide about 200 mg. of iron per kilo of ration (200 parts permillion), and about 15 mg. of copper per kilo. Inthemineral supplement(concentrate) above described, the. iron content is actually about 2000parts per million and the copper content is about 300 parts per million.

I have'found that such high concentrations of iron and copper exert adeleterious effect on the fat and on the vitamin A in- Melnickscompositions. I have noted that as little as 3 parts per million of ironor 0.2 part. per million of copper markedly affects the resistance ofeven hydrogenated fats to oxidative deterioration and of the vitamins A,D, 'E and K contained therein. The observation that the loss of vitaminA parallels peroxide formation in the oil carriers of the vitamin A hasbeen reported by several investigators (Halpern, G. R., Ind. and Eng.Chem., Anal. Ed, vol. 18, p.621 (1946); Dassow l. A. and Stansby, M. E.,J.Amer. Oil Chem. Soc., vol. 26, p. 475 (1949); Kehren cited by Piskur,M. M., J. Amer. Oil Chem; Soc, vol. 27', p. 211 (1950)). Thus, in sup-,plementing mineral mixtures (and even feeds), with the Melnickcomposition, there results not only a dilution of his soybean meal base,but also the exposure of the fat particles, embodying the fat-solublevitamins, to, the

catalytic pro-oxidant effects of iron and copper. As has been mentionedabove, the scientists and technologists who have grappled with theproblem of stabilizingthe fat-soluble vitamins as ingredients of feedsupplements, have sought to achieve protection of those vitamins byembodying them in high-melting fatty substances. Some have even resortedto waxes.

The disadvantage of such recourse was recently announced at the EighthKansas Feed Conference, Kansas State College, Manhattan, Kansas, 1953.During that and will not be absorbed. Thus, while stability isdesirable, a compromise sometimes must be made between stability anddigestibility. a

. In 'order to provide for the physiological availability of thefat-soluble vitamins embodied in such materials, lecithin has also beenincorporated as a component thereof. The lecithin is relied on toprovide an intrinsic emulsifying agent that will make the high meltingvehiclevyield to the digestive processes, and thereby release thevitamin contained therein. .It has been discovered that fat-soluble acidmolecules possess the property, in moisture-free fatty 'medium,ofconverting vitamin A into the unsaturated hydrocarbon, anhydro vitaminA. i

: Thathydrocarbon is biologically inactive. However, it responds to thechemical. colorimetric test (antimony tri-chloride) in a mannersimilar'to the biologically active vitamin A. i 3;; I believe thatlecithin (a fat-soluble acid molecule) has the efiect of inactivatingvitamin A; and'it, therefore,

may in part be responsible -forthe decrease with time (markedlyaccelerated by heat) in the biological potency 'ofvitamin A'preparations which contain substantial quantities of lecithin, viz., upto 5 percent, even when'zthey are blended in an all soybean meal orsoybean flour base. J In the compositions of my aforesaid co-pendingapplication, the lecithinused in making the fatty beads may beresponsible for a 15 percent loss of vitamin A, initially incorporated,as shown, for example, by product C-;of

.Example- 1 therein, which assayed 86 U.S. P. unitsof vitamin A pergram,1=although the theoretical content central core is a solid fat, themelting point of which,

surprisingly, can be substantially below, the high melting points thatheretofore were sought ;for. This discovery that lower melting point'fats can be used successfully makes it possible to omit lecithin; andalso toassure-the physiological availability of the vitamin. The dangersof too efiective sealing the vitamin in discussed by D. P. Parrish,supra, are thus overcome. -In general, the spheres or beads of thepresent invention are less than 2 mm. in diameter. They are manufacturedby dissolving a vitamin bearing oil'or fat-soluble vitamin in the basicmolten fat; adding. (1) this vitamincontaining fat to (2.) an aqueoussolution of the proteinaceous material; heating the mixture of (l)+(2)to a temperature at which the protein could coagulate if the pH weremore favorable; homogenizing the mixture to form an oil in wateremulsion and spray-drying the emulsion. The resulting product is a massof tiny spheres containing the fat-soluble vitamins, each sphere 'beingformed of a fatty vitamin-containing core coated by, or enclosed within,a dry, water resistant proteinaceous film. The .dry vitamin spheresare'free flowing, uniform and similar in structure, andwill not oil of.under regular conditions of storage for indefinite periods.

. The vitamin bearing oils are fish liver oils,.containing vitamin Aand/or vitamin D,'the synthetic vitamins in -an'edible oil solvent or incrystal-line form-preferably ;the former because of improved stabilityprior ,to formuedible oil solvent, and vitamin K in an edibleoil vehicleor in crystalline form.

The fat of the central core of the spheres is one in which thefat-soluble vitamins exhibit excellent stability. Contrary to reportsin, the scientific literature, cited supra, I have discovered that thestability of the vitamins is not necessarily related to the stability ofthe basic fat component of the spheres. Using the active-oxygen method(A.O.M.) described by King, A. E., Roschen, H. L., and Irwin, W. H., Oiland Soap, volume 10, page (1933), involving aeration of the basic fatcomponents at 98 C., I have obtained the values shown in Table I foroxidative stability.

When these oils were used to make the vitamin spheres of this invention,I have obtained the following order of preference in so far as vitaminstability, exemplified by vitamin A stability, is concerned:hydrogenated soybean oil of 50 C. melting point, hydrogenated soybeanoil 435C, melting point, 'hydrogenatedcottonseed oil, limpid corn oil,hydrogenated peanut oil of 45 C; melting point, limpidpeanut .oil,hydrogenated babassu oil, and lastly, hydrogenated coconut oil. However,by supplementing someof these basic fats withantioxidants which arepreferentially soluble in oils, such as butylated hydroxyanisole' to'the extent of 0.02 percent of the fatu'sed, the poorer'fats are madeequal to the best fats 'as a stabilizing vehicle for vitamin A. The useof the more powerful polyphenols, such as propyl gallate, is of no valuein the products of the present invention. Whereas these polyphenols arevery efiective in stabilizing fats, theyjdo not remain in the basic fatcomponent of my preparations but migrate to, and are found in, the outerproteinaceous shell. I In the presence of iron salts in mineral feedmixt'u'res, they impart an objectionable blue discoloration to thevit-amin'spheres. Likewise, acid stabilizers, suchas stability isconcerned, is directly related: to preference based'ontheActive OxygenMethod (A.O.M.) values listed in Table I. i. Vitamin (spheres ofstability superior to that of the prior art can be made without theaddition of fat-soluble antioxidantsjbutfor maximal vitamin retention,particularlywhen the'sphere's are mixed with mineral feed mixtures, theaddition of the butylated hydroxyanisole is I preferred.

Another factor which enters into the selection of the preferred basicfat components of the present invention is the melting point. I now findthat the melting point is far less critical in producing a product whichwill not oil ofl duringordinary conditions of storage. I Indeed,

1 can now use oils that are liquid at room temperature to =form thecores of the spheres. The oil. doesescape glation, carotene in an edibleoil vehicle, vitamin Einan 3 through the proteinaceous shell. However,.the spheres '7 should not :be subjected to high pressures that willffraca ture the shell, as in mixing with other ingredients, in packing"the products, or in stacking flexible packages containing the vitaminspheres.

I prefer to use fats that are solid at room temperature, and especiallythose that remain solid at room temperature, after blending with thevitamin oils. When the vitamins in a liquid oil vehicle are added, Iprefer to use thelhydrogenated fats with a melting point above 45 C.When the vitamins arein crystalline form, or of suchhigh potency thattheliquid oil vehicle is negligible in amount (less than three times .thatof the weight of the vitamin itself), I prefer to use the hydrogenatedfats with am'elting point of 35 C. to 45 C. In other words, mypreference is for a vitamin-basic fat blend with a melting point of 35to 45 C. With the preferred basicfat components of the presentinvention, used according to the above scheme, I obtain vitamin sphereswhich show no oil leakage when held at 45 C. for extended periods, viz.,up to three Weeks. This surprising findingnow makes itunnecessary to usehigh-melting fats (above 50 C.), and thus unnecessary to add lecithin tothe vitamin-fat'blend to render the vitamins physiologically availablefor absorption. By omittingthe lecithin, I find that the products sufferless loss of vitamin A during the heating and spray drying of theemulsion. Of course, high-melting fats, and even waxes, with or withoutadded lecithin, may be used, but these entail disadvantages.-.-decreasedstability or decreased physiological availability of the vitamins-sothat such items are not the preferred vitamin products of thisinvention.

The proteinaceous material used in the products or the present inventionshould contain on the dry basis at least 20 percent of protein andshould be heat coagulable in aqueous solution at a temperature of 65 C.to 85 C. when the pH of the solution is between 4.0 and 5.0.Proteinaceous material that. has already been denatured byheat-processing so that the material is no longer soluble in water,cannot be used in making the products of this invention.Solvent-extracted but not heat-processed soy flour is preferred as thematerial to form the outer protective shell that encases the vitamin-fatcores of the spheres. I have also discovered that other-proteinaceousmaterials such as wheat gluten and low-heat skim milk powder (or skimmilk) serve also as good proteinaceous sources for coating thevitamin-fat spheres. These materials satisfy the above definition of anacceptable proteinaceous component. Combinations of" the proteinaceousmaterials may be employed. The object is to obtain a tough,Water-resistant proteinaceous shell or film around the fat core, i.e.,one that does not release the .fat component simply on the addition ofwater. I rely upon the .proteolytic enzymes in the digestive tract tosolubilize the tough protein film, thereby making the vitamin-fat coreavailable for digestion and absorption.

In making'the products of the present invention the proteinaceousmaterial in water solution, in concentrations of'from 3 to 10 percentexpressed on a protein basis, preferably from 5 to '8 percent, isbrought to a temperature of about '0. above the melting point of thevitamin oil-basic fat blend. The water-soluble B vitamins such asriboflavin, niacin, calcium p'antothenate, and vitamin B may also beadded, dependingv on howbroad a coverage of the vitamin spectrum isdesired in the endproduct.

The fat-soluble vitamin-basic fat blend is prepared separately bydissolving the vitamin oils or synthetic vitamins in the basic fatcomponent held at a temperature of about 10 C. about the melting pointof the fat. The aqueous and fat solutions are mixed, preferably undernitrogen, in a tank equipped with a motor-driven propeller agitator.During the period of agitation of about 10-30 minutes, the mixture isheated to a temperatureof from 65 C. to 85 C. The time and temperatureof heating can be modified. For example, when citric acid isxdissolvled:in the aqueous "phase in concentrations of from 2 to 6 percent of theprotein component, the pH of the aqueous phase decreases from about 6.6to a value of from 6.3 to 6.0. This decrease in pH makes proteincomponents desirably more susceptible 'to heat coagulation. Undersuchcircumstances, it is prefered to heatprocess the aqueous-fat mixture .atabout 65 C. for 'a period of about v10 to 15 minutes to obtain amoistureresistant shell. .In the absence of the added citric'ia'cid, thehigher temperature .andlonger period of heating is preferred. The citricacid in the 'proteinaceous shell encasing the vitamin-fat cores of thespheres serves two useful purposes, viz: (a) it prohibits, by a metalsequestering action, the prooxidant metals, such as iron and copper,from .exerting'their deleterious influence on the labile fat-solublevitamins and on the vfat within the spheres; and (b) itsupplies afavorable stabilizing acid environment in the shell wherein thewater-soluble B vitamins are deposited, should these be included .invtheformulation.

The aqueous-fat mixture with a total solids content of 3.0 to 40percent, water being :added if necessary, 'is then homogenized at apressure 'of 2,000 to 4,000 pounds per square inch. This action leads tothe formation of a fat in water emulsion, i.e., small fat globulesdispersed in the continuous proteinaceous aqueous phase. The emulsion ispreheated in a continuous tubular heat exchanger, and then passedthrough a high pressure pumpneccssary to force the emulsion at apressure of 2,500 to 4,000 pounds per square inch through the nozzles ofthe spray dryer. '1 have found the Rogers No. 20 Spray Dryer of l200-lb.per hour capacity to be highly satisfactory. Spraying Systems core-typenozzleswith removable core and orifice inserts give excellent results.The optimal nozzle opening in the spray-drying operation is about 0:030inch. The temperature of the incoming'hot'air ranges preferably between150 C. to 160 C., and the outgoing air between C. to C. 'In using theGray- Jensen Dryer, a spray nozzle of about 0.06 inch in di-. ameter ispreferred, with the incoming hot air at about C. to C. During thespray-drying operation, the, moisture content of the spheres with theirshells of denatured protein is reduced to a maximum of 2 percent. Anautomatic screw-type unloading gunit continuously removes the productfrom the dryer.. An astonishing'finding in my investigations, is thatthe readily oxidizable vitamins, such as vitamin A, carotene and vitaminE, are destroyed to a negligible degree; less than 10 percent in thespray-drying. operation, despite the use of air of high temperature inthe drying'op'eration. It'is important that'the spheres with thevitamin-fat cores and the coreencasing protective shell be removed fromthe spraydrying chamber as quickly as possible and passed through acooling tunnel. The final'product of particle size less than 2 mm. indiameter is sifted and packaged, preferably in a container'of'stmcturalstrength such as 'a-fibreboard drum.

I believe that the conversion of Water to steam in the drying operationproduces an inert gas (steam) blanket around the spheres protecting themfrom oxidation. The temperature of the spheres is probably well under35C., due to the cooling effect of the evaporating water. Since thetemperature of the spheres climbs as soon as the water It is among theprincipal objects of this invention to provide a dry product containingthe labile, fat-soluble vitamins in the form' of small, city, discrete,spherical bodies comprising a fat-soluble, vitamin-containing coreencased a protective, organic shell.

A further object of this invention is to provide a small, sphericalbody, such as is mentioned above, having an improved protective shellthat is especially resistant to the pro-oxidative effects of minerals;and particularly the pro-'oxidative effects of iron and copper.

A still further object of this invention is to' provide a spherical bodycontaining the fat-soluble vitamins of the class described above whereinthe shell isa heat-denatured, Water-resistant, proteinaceous material.

A'still further objectof this invention is to provide small sphericalbodies containing fat-soluble vitamins wherein the proteinaceo-us shellis derived from soy flour.

An additional object of this invention is to provide the sphericalbodies containing the fat-soluble vitamins, as described above, whereinthe protective, encasing shell also contains water-soluble vitamins ofthe'vitamin B complex. An even further object of this invention is toprovid for the stabilization of vitamins embodied in high-melting fatsby omitting lecithin, which has heretofore been considered necessary toassure the physiological availability of the vitamins.-

- A further object of this invention is to provide a feed concentrate ofhigh mineral content containing iron and copper and also the labile,fat-soluble vitamins that is characterized by marked stability of thelabile vitamins when said feed concentrate is stored for long periods oftime.

A still further object of this invention is to provide feed supplementscontainingboth minerals and the fat-soluble vitamins which stockrnen andpoultrymen can add to the basic grains and forage that are availablelocally to them in order to provide their livestock with nutritionallyWellbalanced rations.

A still further object of this invention is to provide a novel means, asby the use of an external barrier citric acid, to interact withpro-oxidant minerals, particularly iron and copper, and thereby insulatethe labile, fatsoluble vitamins, especially vitamin A, from thedestructive effects of said minerals.

The foregoing objects as well as further objects and advantages of thisinvention will become apparent from the following detailed descriptionthereof as exemplified by (a) my initial discoveries and fundamentalconception that the fat-soluble vitamins are most effectively sta- 10mixture is homogenized at a pressure of 3,000 pounds per square inch toyield a fat in water emulsion.

The emulsion containing about 32-33 percent of solids is spray dried asdescribed above to produce dry, discrete beads or spheres (hereinafterreferred to as the final product). This-final product has the physicalstructureofa vitamin-fat core encased within a protective sphericalcoating of the water-resistantheat-denatured protein film,. the diameterof the spheres measuring less than 2 mm.- and the spheres containingless than 1 percent moisture.- The ratio of the fatty-vitamin-containingcore to the p tective coating is as 75 :25.

w Assays conducted on the final product as thus manufac-- turedindicateda vitamin A content of 11,000,000 U.S.P.

532 units per gram while the vitamin D remained constant at 1854190units per gram. In complete feed mixtures made from this final product,simulating the complete feed mixtures described by Melnick, nomeasurable losses of the vitamins were noted after the 21-day holdingtest at C.

. In the above and following examples, A.O.A.C. units of vitamin Daresynonomous with International Chick j quinone). The mixture isstirred under nitrogen for a bilized and protected when they arecomponentsof beads 1 In one tank 97.0 parts of coconut oil, hydrogenatedto an iodine'number of 1.0 and'having amelting point of I 37 C., isheated to about 47-C. To this are added 0.02 p'ar't of bultylatedhydroxyanisole, 0.025par't of crystalline vitamin D of a potency of40,000,000A.O .A.C. units per gram, and 3.0 parts of vitamin Apalmitateii'i 60m oil having a potency of 1,100,000 U.S.P. units pergram. The mixtureis stirred under nitrogen fora period of about. 15minutes to eifect a clear solution, 7

' In anotherltank 31 parts 'of solvent-extracted nonheat-processed soyflour containing about 50 percent pro-. I tein (nitrogen 6.25) aresuspended in 300 parts of warm. H 70 water at about40 C. and stirred fora period of about 15 minutes until the soy flour is'dissolved. Two partsof citric acid are then dissolved in this solution.

' The contents of the two tanks are mixed under nitrogen and heated bysteam coils to a temperature or about 65 C; for a period of 20- minutes.'The aqueous-fat period of about 15 minutes to effect a clear'solution.

In another tank 100 parts of skim-milk powder (low heat) are suspendedin 400 parts of water; and the temperature brought to about 55 C. p

i The contents of the two tanks are mixed under nitrogen and heated bysteam coils for a period of 30 minutes, at a temperature of C. Thisaqueous-fat mixture is then homogenized, as described in Example 1, andspray dried to produce dry discrete spheres in accordance with .themethod described in Example 1 The product of this example are lsphereshaving a diameter of less'than 2 mm. They aresimilar in physicalstructure to the product of Example 3, consisting of afat-containingvitamin core encased within a protective shell orcoating-of water-resistant heat-denatured protein. Theratioof ,the fattycore to the proteinaceous shell is as 50c50.

indicated the following potencies per pound:

vitam'm Found Calculated Component Vitamin A- 4,090,000 USP units.--3,700,000 USP units. V tamin D; 1,820,000 AOAO units 1,800,000 AOACunits.

Vitamin E- 4,000 mg 4,150 mg.

227,000 AOAC units 220,000 AOAO units.

Vitamin K;

257 (1944). Vitamin K was determined by the blood clottingassay"withchicks (A.O.A.C., Sixth Edition 11 T (1945)). With the exception ofvitamin A, of which a loss of about percent was experienced, nosignificant losses of Vitamins were noted in the production of theabove" product. The increase in vitamin E is attributable to the factthat the soybean oil, the fatty component, contributes measurablequantities of tocopherols.

I When one part of the product of this example is added to 14 parts ofthe minerals supplement or concentrate above described, and this mixtureof minerals and vitamins is stored at C. for a period of 21 days, fully80 percent of the vitamin A and more than 90 percent of the othervitamins were retained. Complete feed mixtures made with the product ofthis example, simulating the complete feed mixtures described byMelnick, showed retentions of more than 90 percent of the vitamins afterthe 21-day holding test at 45 C. It is to be noted that the surprisingstability of the product of this example, containing no free soybeanflour or soybean meal, is in sharp contrast to the reports in thescientific literature and the teaching of Meinick. They reported thatthe soybean meal in order fully to stabilize the vitamin A.

Example 3 in one tank, 94.0 parts of hydrogenated babassu oil,hydrogenated to an iodine number of 1.0 and having a melting point of 44C., is heated to about C. To this are added 0.02 part of butylatedhydroxyanisole, 1.0 part of vitamin A acetate concentrate (2,400,000U.S.P.' nnits/ gram), 0.015 part of crystalline vitamin D (40,

A.G.A.C. units/ gram), 5.0 parts of vitamin E in cottonseed oil (35percent mixed tocopherols), and 0.10 part of crystalline vitamin K(2-methyl-l,4-naphthoquinone). The mixture is stirred under nitrogentoetfect a clear solution.

' In another tank 50.0 parts of solvent-extracted, nonheat processedsoybean flour, 41.0 parts of skim-milk powder (iow teat) and 1.8 partsof citric acid are suspended in 400 parts of warm water and stirreduntil the soy flour is dissolved. Then to this solution thereare partsof calcium pantothenate, 0.0036part of vitamin of less than 2 mm., thespheres being similar in structure to those above described. The ratioof the fatty core to the water-resistant, heat-denatured, protective:coating is as 50:50. The fat-soluble vitamins are present in the coresof said spheres in a highly stable fat containing the added butylatedhydroxyanisole which overcomes the deficiency of the base fat in fullyprotecting-the labile,

. fat-soluble vitamins. The water-resistant shell encasing the fattycore containcitric acid which prevents the prooxidant effects of ironand copper in mineral mixtures and in feeds from exerting theirdestructive eifects on.

the fat-soluble vitamins. The stability of the fat-soluble vitaminsduring the spray-drying operation, and .during subsequent storage of thespherical bodies as such in the mineral mixture (concentrate), describedsupra, and in feeds was comparable to that noted for--the-vitamins A andD in Example 1 and for theother'vitamins in Example 2. V Thewater-soluble B vitamins are embedded. in a heatdenatured, proteinmatrix of pH about 6.2 that constitutes the encasing shell for thecores. Those watersoluble vitamins exhibit superior stability in thatenvironment. The high-heat treatment in a somewhat acid environmentprior to the spray-drying is especially desirgastric acidity.

aces-gent 12 able. ineliminatingthe reducing activity of skiin -milksolids which I believe is responsible for excessive vitamin B losses inconventionally spray-drying skim-milk, preheated at the lowertemperature of about 65 C.

It will be observed that the products of this invention arecharacterized, inter alia, by having a structure in which thefat-soluble vitamins are present in a core of exceedingly small sizethat is encased 'by a dry, waterresistant, heat-denatured, proteinprotective shell. When suspended inwater and agitated the sphericalbodies do not readily release the fat component.

Since the melting point of the fat employed in building the sphericalbodies is sensibly less than the melting points of the materials usedfor sealing the vitamin in in the products mentioned by Parrich supra, Ihave investigated the physiological availability of the vitamins in mynovel spherical bodies. Use was made of the criteria of growth responseand feed consumption of day-old chicks subsisting on a basal adequateration but free of vitamin A, supplemented inone series with theproducts of the present invention and in another with a vitamin Afeeding oil, and in another with the USP. Vitamin A Reference Standard.It was discovered that the vitamin A in the products of this inventionwere actually utilized, unit for unit, more eificiently than the vitaminA in the form of either the commercial feeding oil or the U.S.P.Reference Standard. The growth response during the 8-week test period inrelation to physicochemical assay, indicated vitamin A potencies about15 percent greater in the case of the products of this invention. Thefeed efficiencygrams gain in body weight per grams consumedwas 60 to 100percent superior with the rations containing the products of the presentinvention when compared with the'rations containing the vitamin Afeeding oil. I believe that the water-resistant protein protectiveshells that encase the fat-soluble, vitae min-containing cores of mynovel beads are not readily digestable until the product enters thesmall intestine. At this point, proteolytic activity removes completelythis outer layer leaving the fat core available for digestion andabsorption. When vitamin A in an oil vehicle, such as in the commercialfeeding oil, enters the stomach partial destruction of the vitamin Aoccurs due in part to In other words, the products .of this inventionare not only far more stable in vitro but also in vivo when comparedwith vitamin A in an oil vehicle.

This explains the ,greater-than-theoretical vitamin A potency of theproducts of this invention.

The ratio of the core containing the fat-soluble vitamins to theencasing protective shell should not be less than as 40 to 60,v and notmore than as 90 to 10.

Preferably, the protein content of the shell should be at least 20percent.

When citric acid is incorporated in the proteinaceous shell, it shouldnot be present in an amount exceeding 6 percent; and thelower rangeshould be preferably about 2 percent.

If an anti-oxidant such as butylated hydroxyanisole is used, it ispreferable not to incorporate more than 0.1 percent thereof.

The fat-soluble vitamin content of the fatty core will depend upon thedesired vitamin potency of the beads;

such potency being adjustable with respect to the man- 1 ner in whichthe beads are to be used. Since these .stabilized, fat-soluble,vitamin-containing beads are supplements to be incorporated in the feedration, either directly or as components of a mixed mineral-vitaminsupplement or the like, the potencies should be such that it will beeasy to incorporate a sufiicient bulk of the supplements in the mass ofthe ration as to prepare a ration having a uniform potency of requisitenutritional level.

It will be understood that the foregoing description of this inventionand the exemplary embodiments set forth are merely illustrative of theprinciples thereof; and, accordingly, that the appended claims areto beconstrued as defining the invention within the full spirit and scopethereof. i

I claim:

1. Process of making dry, discrete beads containing stabilizedfat-soluble vitamin in a fatty core which is encased in a heatdenatured, water-resistant proteinaceous digestible shell, said processcomprising mixing a solution of fat-soluble vitamin in a fat having amelting point of about at least 35 C., at a temperature of about 10 C.above the melting point of the fat with an aqueous solution of a heatcoagulable, proteinaceous material, heating the mixture to about 65 85C. for a period of about 10-30 minutes, homogenizing said mixturecontaining about 30% to 40% of-total solids to form an emulsion with theoil as the finely dispersed internal phase, and spray drying said heatedemulsion to complete the denaturation.

2. Process of making dry, discrete beads containing stabilizedfat-soluble vitamin in a fatty core which is encased in a heatdenatured, water-resistant proteinaceous digestible shell, said processcomprising mixing a solution of fat-soluble vitamin in a fat having amelting point of about at least 35 C., at a temperature of about 10 C.above the melting point of the fat with an aqueous solution of a heatcoagulable, proteinaceous material, and citric acid, heating saidmixture having a pH of about 6.0-6.3 to about 65 -85 C. for ;a period ofabout 10-30 minutes, homogenizing said mixture containing about 30% to40% of total solids to form an emulsion with the oil as the finelydispersed internal phase, and spray drying said heated emulsion to com-'plete the denaturation.

3. Process in accordance with claim 1, wherein the fat soluble vitaminis vitamin A. a

4. Process in accordance with claim 2, wherein the fat soluble vitaminis vitamin A.

7. Dry, discrete beads in accordance with claim 6 wherein thefat-soluble vitamin is vitaminA.

References Cited in the file of this patent UNITED STATES PATENTS1,622,390 Miller Mar. 29, 1927 2,206,113 'Nitardy July 2, 1940 2,218,592Taylor Oct. 22, 1940 2,283,531 Briod May 19, 1942 2,410,455 Musher Nov.5,1946 2,650,895 Wallenmeyer et al ..'Sept. 1, 1953 FOREIGN PATENTS297,256 Great Britain Sept. 20, 1928 301,651 Great Britain Dec. 6, 1928681,931 Great Britain Oct. 29, 1952 OTHER REFERENCES Sandell: QuarterlyJournal of Pharmacy and Pharmacology, January-March 1947, p. 68.

Burns: Industrial and Engineering Chemistry, vol. 43, July 1951, pp.1592, 1593.

1. PROCESS OF MAKING DRY, DISCRETE BEADS CONTAINING STABILIZEDFAT-SOLUBLE VITAMIN IN A FATTY CORE WHICH IS ENCASED IN A HEATDENATURED, WATER-RESISTANT PROTEIN ACEOUS DIGESTIBLE SHELL, SAID PROCESSCOMPRISING MIXING A SOLUTION OF FAT-SOLUBLE VITAMIN IN A FAT HAVING AMELTING POINT OF ABOUT AT LEAST 35*C., AT A TEMPERATURE OF ABOUT 10*C.ABOVE THE MELTING POINT OF THE FAT WITH AN AQUEOUS SOLUTION OF A HEATCOAGULABLE PROTEINACEOUS MATERIAL, HEATING THE MIXTURE TO ABOUT65*-85*C. FOR A PERIOD OF ABOUT 10-30 MINUTES, HOMOGENIZING SAID MIXTURECONTAINING ABOUT 30% TO 40% OF TOTAL SOLIDS TO FORM A EMULSION WITH THEOIL AS THE FINELY DISPERSED INTERNAL PHASE, AND SPRAY DRYING SAID HEATEDEMULSION TO COMPLETE THE DENATURATION.